It is often desirable to provide a hydrophilic coating (e.g., anti-fog coating) on a substrate such as an automotive windshield, automotive window, automotive mirror, architectural mirror, bathroom mirror, or the like. Such coatings may reduce the likelihood of water drops deposited on the substrate taking globular shape(s), thereby enabling visibility to be improved. In other words, hydrophilic coatings function to reduce bead-like condensation on substrate surfaces (e.g., on the interior surface of an automotive windshield or window). A hydrophilic coating can reduce the formation of many tiny droplets of liquid, which can scatter light, on a surface (i.e., make condensation on a surface film-wise as opposed to droplet-wise).
Unfortunately, certain hydrophilic coatings are not as durable and/or hard as would otherwise be desired and thus are not efficient from a practical point of view for applications such as automotive windshields and/or windows. Furthermore, conventional hydrophilic coatings often cannot withstand high temperatures without breaking down or being damaged. The ability to withstand high temperatures is useful in applications such as automotive windshields where it may be desirable to anneal and/or bend a coated glass article at high temperature(s) after the coating has been deposited.
In view of the above, it is apparent that there exists a need in the art for (i) a coated article (e.g. coated glass or plastic substrate) having hydrophilic properties, and a method of making the same, (ii) a hydrophilic coating capable of withstanding high temperatures (e.g., up to 600 degrees C., and/or even up to 700 degrees C. in certain embodiments) without being substantially damaged (e.g., burned/burning) or breaking down, and/or (iii) a protective hydrophilic coating for window and/or mirror substrates that is somewhat resistant to scratching, damage, or the like.
It is a purpose of different embodiments of this invention to fulfill any or all of the above described needs in the art, and/or other needs which will become apparent to the skilled artisan once given the following disclosure.